Del-Tron Precision's Tech-Info Slides and Rollers 101

Del-Tron Precision began operations in 1974 supplying original equipment manufacturers with the world's first commercially available subminiature linear bearings. Since then, thousands of Del-Tron ball slides have been incorporated into medical analyzing and testing machines, semi-conductor processing equipment, computer peripherals, assembly systems, scientific instruments and many other machines. The technical information below covers most of the main design considerations Del-Tron uses.

1. Ball Slide or Roller Slide Type Linear Bearing:

• Ball slide design advantages:
  • Self-cleaning (point contact of balls and shafts does not allow foreign material to interfere).
  • Low cost (ball and shaft materials are common and easily manufactured).
• Crossed roller slide design advantages:
  • Line contact of roller to shafts offer 8x10 times the load capacity of balls.
  • Higher over hanging load capacity and low axial play.

2.  Straight Line Design or Recirculating Type:
Straight line or non-recirculating linear bearings have rolling elements which move on a straight track and are separated by a retainer. This type of linear bearing reaches the end of its travel when the retainer or rolling element contacts a limiting component, (either a screw head or end cap). This travel limitation is determined by the relationship of the retainer length to the carriage length. Standard linear bearings usually have travel equal to 1/3 the carriage length. Maximum total travel can be as much as 1x the carriage length. Therefore, for more travel you must specify a longer slide. This design offers extermely low friction and stiction characteristics.

3. Custom Slides and Linear Bearings:
Del-Tron's engineering staff will be pleased to assist you in developing custom versions of our linear slides. Our proprietary manufacturing processes allow us to offer completely customized slides built to your requirements even in small quantities in less than eight weeks.

• Changes in height, wideth, or length
• More or less travel
• Increased load capacity
• Light, medium, or heavy pre-load
• Different holes, threads or hole locations
• Dowel holes and pins
• Reduced or increased axial play
• Multiple carriages on a single base
• Non-standard retainer material
• Non anodize or non-standard anodize color
• Corrosion resistant stainless stell components

4. High Temperature Applications:
Del-Tron slides can be modified to operate in elecated temperature areas by the substitution of teflon, aluminum, or brass retainers.

5. Static Sensitive Applications
Del-Tron now offers precision linear motion devices that meet low electrostatic discharge requirements common in the semi-conductor and electronics industries. The new linear bearings are coated with electroless nickel, an alloy of nickel and phosphorous produced by autocatalytic chemical reduction with hypophosphite. The plating allows static charges to dissipate, helping the slides to meet requirements for automated equipment. Del-Tron's "ESD" electroless nickel plated linear bearing are plated to ASTM standard B 733.97. This process is available for Del-Tron's line of ball slides, crossed roller slides and both ball and crossed roller multi-axis positioning stages.

6. Vacuum Applications
Outgassing of slide components can be reduced or eliminated for vacuum applications by eliminating anodized and oxide finishes, labels, lubricants, and non-metallic retainers.

7. Preload vs. Axial Play
Many of our linear bearings are built to allow the preload to be set to a specific amount to accommodate the needs of the application. A light, medium, or heavy preload may be ordered. The amount of preload can expressed as grams of force needed to move either the base or carriage. Please contact our application engineers to discuss your special preload requirements.

Slide preload and axial play are related.

• Increased preload = Less axial play
• Decreased preload = more axial play

Del-Tron's DL series linear actuators offer the benefits of a space-saving design, fast and simple assembly, long-life, and at a competitive price. The rigid enclosed aluminum box structure provides a compact envelope that incorporates the linear bearing and drive mechanism. Integrating all components into a single unit that includes the motor adaptor saves assembly time and eliminates the need to source additional parts. DL series linear actuators are offered in travel lengths up to 410 millimeters. These ball and lead screw driven actuators utilize recirculating guide technology to provide a low profile and compact design solution.

The anti-backlash lead screw nut is spring-loaded to ensure positive movement when changing direction. The units offer straight-line accuracy of less than 2 microns and repeatability of less than 1 micron. A standard stepper or servo motor adaptor and coupling are provided at no additional charge. Other motor adaptors and motor coupling can be provided at your request. Photoelectric or proximity position sensors are available. An anti-dust containment cover protects moving components while also preventing particulate emissions. Load capacities range from 150 newtons to 900 newtons. Del-Tron can provide special leads, diameters, couplings, motor mounts, and vary the size, type and travel of slides on request. For your convenience solid model drawings for our entire product line are available on our website and we are always ready to discuss any special needs or modifications you may require.